Optic fiber connection for a force sensing instrument

ABSTRACT

A surgical instrument that includes a housing linkable with a manipulator arm of a robotic surgical system, a shaft coupled to the housing, a force transducer on a distal end of the shaft, and a plurality of fiber optic strain gauges on the force transducer is disclosed. The plurality of strain gauges are coupled to a fiber optic splitter or an arrayed waveguide grating (AWG) multiplexer, which can be coupled to a fiber optic connector. A wrist joint coupled to an end effector is coupled to a distal end of the force transducer. A robotic surgical manipulator that includes a base link coupled to a distal end of a manipulator positioning system, and a distal link with an instrument interface, and a fiber optic connector optically linkable to a surgical instrument. A method of passing data between an instrument and a manipulator via optical connectors is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PATENTS

This application is a continuation application of U.S. application Ser.No. 12/415,795 filed Mar. 31, 2009, which is related to U.S. applicationSer. No. 11/537,241, filed Sep. 29, 2006, which claimed priority to U.S.Provisional Application No. 60/755,108 filed Dec. 30, 2005, the fulldisclosures of which are incorporated by reference herein for allpurposes.

This application is further related to U.S. Provisional Application60/755,157 filed Dec. 30, 2005, U.S. application Ser. No. 11/958,772filed Dec. 18, 2007, U.S. application Ser. No. 11/864,974 filed Sep. 29,2007, U.S. application Ser. No. 11/553,303 filed Oct. 26, 2006, U.S.patent application Ser. No. 11/093,372 filed Mar. 30, 2005, and U.S.Pat. Nos. 6,936,042, 6,902,560, 6,879,880, 6,866,671, 6,817,974,6,783,524, 6,676,684, 6,371,952, 6,331,181, and 5,807,377, the fulldisclosures of which are incorporated by reference herein for allpurposes.

TECHNICAL FIELD

The present invention relates generally to surgical robot systems and,more particularly, to apparatus and methods for data communicationrelated to sensing forces applied to a surgical instrument and/or asurgical robotic manipulator.

BACKGROUND

In robotically-assisted surgery, the surgeon typically operates a mastercontroller to control the motion of surgical instruments at the surgicalsite from a location that may be remote from the patient (e.g., acrossthe operating room, in a different room or a completely differentbuilding from the patient). The master controller usually includes oneor more hand input devices, such as handheld wrist gimbals, joysticks,exoskeletal gloves, handpieces or the like, which are operativelycoupled to the surgical instruments through a controller with servomotors for articulating the instruments' position and orientation at thesurgical site. The servo motors are typically part of anelectromechanical device or surgical manipulator arm (“the slave”) thatincludes a plurality of joints, linkages, etc., that are connectedtogether to support and control the surgical instruments that have beenintroduced directly into an open surgical site or through trocar sleevesinserted through incisions into a body cavity, such as the patient'sabdomen. Depending on the surgical procedure, there are available avariety of surgical instruments, such as tissue graspers, needledrivers, electrosurgical cautery probes, etc., to perform variousfunctions for the surgeon, e.g., retracting tissue, holding or driving aneedle, suturing, grasping a blood vessel, or dissecting, cauterizing orcoagulating tissue.

This method of performing telerobotic surgery through remotemanipulation has created many new challenges. One such challenge isproviding the surgeon with the ability to accurately “feel” the tissuethat is being manipulated by the surgical instrument via the roboticmanipulator. The surgeon must rely on indications of the forces appliedby the instruments or sutures. It is desirable to sense the forcesapplied to the tip of the instrument, such as an end effector (e.g.,jaws, grasper, blades, etc.) of robotic endoscopic surgical instruments,in order to feed the forces back to the surgeon user through the systemhand controls or by other means such as visual display or audible tone.

A surgeon may employ a large number of different surgicalinstruments/tools during a procedure. Some of the surgical instrumentsmay include fiber optic force sensors on multiple optic fibers, and itis desirable to make a reliable and robust optical connection with thesurgical system when the instrument is electrically and mechanicallymounted to the robotic manipulator. It is also desirable to combine thesignals from multiple sensor fibers into one fiber to improve opticalconnection.

What is needed, therefore, are improved telerobotic systems, apparatus,and methods for remotely controlling surgical instruments at a surgicalsite on/in a patient. In particular, these systems, apparatus, andmethods should be configured to provide accurate feedback of forces tothe surgeon to improve user awareness and control of the instruments andmanipulator.

SUMMARY

The present invention provides a surgical instrument, manipulator, andmethod for improving force feedback to and sensing by a surgeonperforming telerobotic surgery. In particular, a surgical instrumentcomprises a housing including an optic fiber connector that is opticallylinkable with a manipulator arm of a robotic surgical system, a shaftoperably coupled to the housing, and a plurality of strain gauges on aforce transducer on a distal end of the shaft, the plurality of straingauges operably coupled to the optic fiber connector. The instrumentfurther includes a wrist joint operably coupled to the distal end of theforce transducer, and an end effector operably coupled to the wristjoint.

In another embodiment, a robotic surgical manipulator comprises amanipulator arm, including a base link operably coupled to a manipulatorpositioning arm and a distal link of the manipulator arm, movablycoupled to the base link. The distal link includes an instrumentinterface and an optic fiber connector optically linkable to a surgicalinstrument.

In yet another embodiment, a method of force sensing at the tip of arobotic surgical instrument comprises providing a robotic surgicalmanipulator including a first optic fiber connector, and mounting aremovable surgical instrument on the robotic surgical manipulator, thesurgical instrument including a plurality of strain gauges on a forcetransducer on a distal end of a shaft and a second optic fiber connectorthat is optically linkable with the first optic fiber connector of themanipulator. The method further includes passing data from the pluralityof strain gauges to the first optic fiber connector through the secondoptic fiber connector.

The scope of the invention is defined by the claims, which areincorporated into this section by reference. A more completeunderstanding of embodiments of the present invention will be affordedto those skilled in the art, as well as a realization of additionaladvantages thereof, by a consideration of the following detaileddescription of one or more embodiments. Reference will be made to theappended sheets of drawings that will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of a robotic surgical environment in accordancewith an embodiment of the present invention.

FIG. 1B illustrates a perspective view of an embodiment of a roboticsurgical manipulator system.

FIG. 2A illustrates a perspective view of a force sensing roboticsurgical instrument, and FIG. 2B illustrates an enlarged view of adistal end of the surgical instrument in accordance with an embodimentof the present invention.

FIGS. 3A and 3B show orthographic views of planar lightwave circuit(PLC) and fused biconic taper (FBT) fiber optic splitters, respectively.

FIGS. 4A and 4B are longitudinal cross-section views of lensed opticalfiber, which are components of some embodiments of the presentinvention.

FIG. 5 illustrates a type of fiber collimator comprising a housing, anaspheric lens and an optic fiber in focal alignment, that may be used asan expanded beam fiber optic connector in embodiments of the presentinvention.

FIGS. 6A1 and 6A2 illustrate a perspective view and a partial cutawayperspective view, respectively, of a PLC fiber optic splitter operablycoupled to a gradient index (GRIN) lens collimator.

FIGS. 6B1 and 6B2 illustrate a perspective view and a partial cutawayperspective view, respectively, of a PLC fiber optic splitter operablycoupled to a ball lens collimator.

FIG. 7A illustrates a surgical instrument with a force transducercomprising a plurality of fiber Bragg grating strain gauges operablycoupled to a PLC fiber optic splitter, and FIG. 7B illustrates anenlarged view of a distal end of the surgical instrument with the forcetransducer.

FIGS. 8A, 8B, and 8C show different views of a tapered slot feature ofan instrument sterile adaptor guiding and aligning a pair of flexiblymounted lensed fiber optic connectors.

FIGS. 9A, 9B, and 9C show different views of a conically tapered featureof an instrument sterile adaptor guiding and aligning a pair of flexiblymounted lensed fiber optic connectors.

FIGS. 10A-10D show orthographic views of an instrument rear housingincluding a fiber optic ribbon cable, a PLC fiber optic splitter, astrain relief loop of optical fiber or ribbon cable and an expanded beamoptic fiber connector in accordance with an embodiment of the presentinvention.

FIG. 11 is a perspective view of a surgical robotic manipulatorincluding an optic fiber connector at an instrument interface of thedistal link of the manipulator, the manipulator coupled to a fiber opticstrain interrogator and a controller, in accordance with an embodimentof the present invention.

FIG. 12A is a perspective view of the manipulator of FIG. 11, includingthe optic fiber connector and including the coupling of a sterileadaptor to the instrument interface that allows for the use of the opticfiber connector, in accordance with an embodiment of the presentinvention.

FIG. 12B is an enlarged view of the sterile adaptor, and FIG. 12C is anenlarged sectional view of the sterile adaptor coupled to the distallink instrument interface in accordance with an embodiment of thepresent invention.

FIG. 13A is a perspective view of the manipulator of FIG. 12A, includingthe coupling of an instrument having a mating optic fiber connector, inaccordance with an embodiment of the present invention.

FIG. 13B is an enlarged sectional view of the instrument mounted to thesterile adaptor mounted to the distal link in accordance with anembodiment of the present invention.

Embodiments of the present invention and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures. It should alsobe appreciated that the figures may not be necessarily drawn to scale.

DETAILED DESCRIPTION

The present invention provides a multi-component system, apparatus, andmethod for sensing forces while performing robotically-assisted surgicalprocedures on a patient, particularly including open surgicalprocedures, neurosurgical procedures, and minimally invasive endoscopicprocedures, such as laparoscopy, arthroscopy, thoracoscopy, and thelike. The system and method of the present invention are particularlyuseful as part of a telerobotic surgical system that allows the surgeonto manipulate the surgical instruments through a servomechanism from alocation remote from the patient. To that end, the combined manipulatorapparatus or slave and the attached surgical instrument of the presentinvention will usually be driven by a master having equivalent degreesof freedom (e.g., 3 degrees of freedom for position, 3 degrees offreedom for orientation plus grip) to form a telepresence system withforce reflection or display. A description of a suitable slave-mastersystem can be found in U.S. Pat. No. 6,574,355, the complete disclosureof which is incorporated herein by reference for all purposes.

A robotic system of the present invention generally includes one or moresurgical manipulator assemblies mounted to or near an operating tableand a master control assembly for allowing a surgeon to view thesurgical site and to control the manipulator assemblies. The system willalso include one or more viewing scope assemblies and a plurality ofsurgical instruments adapted for being removably coupled to themanipulator assemblies (discussed in more detail below). The roboticsystem includes at least two manipulator assemblies and preferably atleast three manipulator assemblies. As discussed in detail below, one ofthe assemblies will typically operate a viewing scope assembly (e.g., inendoscopic procedures) for viewing the surgical site, while the othermanipulator assemblies operate surgical instruments for performingvarious procedures on a patient.

The control assembly may be located at a surgeon's console which isusually located in the same room as the operating table so that thesurgeon may speak to his/her assistant(s) and directly monitor theoperating procedure. However, it should be understood that the surgeoncan be located in a different room or a completely different buildingfrom the patient. The master control assembly generally includes asupport, a monitor for displaying an image of the surgical site to thesurgeon, and one or more master(s) for controlling the manipulatorassemblies. Master(s) may include a variety of input devices, such ashand-held wrist gimbals, joysticks, gloves, trigger-guns, hand-operatedcontrollers, voice recognition devices, or the like. Preferably,master(s) will be provided with the same degrees of freedom as theassociated manipulator with surgical instrument assemblies to providepart of the surgeon telepresence, the perception that the surgeon isimmediately adjacent to and immersed in the surgical site, andintuitiveness, the perception that the master(s) are integral with theinstruments so that the surgeon has a strong sense of directly andintuitively controlling instruments as if they are part of his or herhands. Position, force, and tactile feedback sensors may also beemployed on instrument assemblies to transmit signals that may be usedto represent position, force, and tactile sensations from the surgicalinstrument back to the surgeon's hands as he/she operates thetelerobotic system. One suitable system and method for providingtelepresence to the operator is described in U.S. Pat. No. 6,574,355,which has previously been incorporated herein by reference.

The monitor will be suitably coupled to the viewing scope assembly suchthat an image of the surgical site is provided adjacent the surgeon'shands on the surgeon console. Preferably, the monitor will display animage on a display that is oriented so that the surgeon feels that he orshe is actually looking directly down onto the operating site. To thatend, an image of the surgical instrument appears to be locatedsubstantially where the operator's hands are located and orientedsubstantially as the operator would expect it to be based on his/herhand positions. In addition, the real-time image is preferably a stereoimage such that the operator can manipulate the end effector and thehand control as if viewing the workspace in substantially true presence.By true presence, it is meant that which the operator would see ifdirectly viewing and physically manipulating the surgical instruments.Thus, a controller transforms the coordinates of the surgicalinstruments to a perceived orientation so that the stereo image is theimage that one would see if, for example, the camera or endoscope waslocated directly behind the surgical instruments. A suitable coordinatetransformation system for providing this virtual image is described inU.S. patent application Ser. No. 08/239,086, filed May 5, 1994, now U.S.Pat. No. 5,631,973, the complete disclosure of which is incorporatedherein by reference for all purposes.

A servo control is provided for transferring the mechanical motion ofmasters to the manipulator assemblies. The servo control may provideforce and torque feedback from the surgical instruments to thehand-operated masters. In addition, the servo control may include asafety monitoring controller to safely halt system operation, or atleast inhibit all robot motion, in response to recognized undesirableconditions (e.g., exertion of excessive force on the patient, mismatchedencoder readings, etc.).

Referring now to the drawings in detail, wherein like numerals indicatelike elements, FIGS. 1A-1B illustrate components of a robotic surgicalsystem 1 for performing minimally invasive robotic surgery in accordancewith an embodiment of the present invention. System 1 is similar to thatdescribed in more detail in U.S. Pat. No. 6,246,200, the full disclosureof which is incorporated herein by reference.

A system operator O (generally a surgeon) performs a minimally invasivesurgical procedure on a patient P lying on an operating table T. Thesystem operator O sees images presented by display 12 and manipulatesone or more input devices or masters 2 at a surgeon's console 3. Inresponse to the surgeon's input commands, a computer processor 4 ofconsole 3 directs movement of surgical instruments or tools 5, effectingservo-mechanical movement of the instruments via a robotic patient-sidemanipulator system 6 (a cart-based system in this example) includingjoints, linkages, and manipulator arms each having a telescopicinsertion axis. In one embodiment, processor 4 correlates the movementof the end effectors of tools 5 so that the motions of the end effectorsfollow the movements of the input devices in the hands of the systemoperator O.

Processor 4 will typically include data processing hardware and softwareto implement some or all of the methods described herein. Whileprocessor 4 is shown as a single block in the simplified schematic ofFIG. 1A, the processor may comprise a number of data processingcircuits, with at least a portion of the processing optionally beingperformed adjacent an input device, a portion being performed adjacent amanipulator, and the like. Any of a wide variety of centralized ordistributed data processing architectures may be employed. Similarly,the programming code may be implemented as a number of separate programsor subroutines, or may be integrated into a number of other aspects ofthe robotic systems described herein.

In one example, manipulator system 6 includes at least four roboticmanipulator assemblies. Three setup linkages 7 (mounted at the sides ofthe cart in this example) support and position manipulators 8 withlinkages 7 in general supporting a base link 30 of the manipulators 8 ata fixed location during at least a portion of the surgical procedure.Manipulators 8 move surgical tools 5 for robotic manipulation oftissues. One additional linkage 9 (mounted at the center of the cart inthis example) supports and positions manipulator 10 which controls themotion of an endoscope/camera probe 11 to capture an image (preferablystereoscopic) of the internal surgical site. The fixable portion ofpositioning linkages 7, 9 of the patient-side system is sometimesreferred to herein as a “setup arm”.

Assistant A assists in pre-positioning manipulators 8 and 10 relative topatient P using setup linkage arms 7 and 9, respectively; in swappingtools 5 from one or more of the surgical manipulators for alternativesurgical tools or instruments 5′; in operating related non-roboticmedical instruments and equipment; in manually moving a manipulatorassembly so that the associated tool accesses the internal surgical sitethrough a different aperture, and the like.

In general terms, the linkages 7, 9 are used primarily during setup ofpatient-side manipulator system 6, and typically remain in a fixedconfiguration during at least a portion of a surgical procedure.Manipulators 8, 10 each comprise a driven linkage which is activelyarticulated under the direction of the surgeon at console 3. Althoughone or more of the joints of the setup arm may optionally be driven androbotically controlled, at least some of the setup arm joints may beconfigured for manual positioning by assistant A.

In one example, the image of the internal surgical site is shown tooperator O by a stereoscopic display 12 in surgeon's console 3. Theinternal surgical site is simultaneously shown to assistant A by anassistance display 14.

Some of the manipulators may include a telescopic insertion axis (e.g.,telescopic insertion axis 60 of FIGS. 11, 12A and 13A), although inother embodiments, all of the manipulators may include a telescopicinsertion axis. Telescopic insertion axis 60 allows for movement of amounted instrument (e.g., instrument 5 of FIG. 1A or instrument 100 ofFIG. 13A-13B), via three operably coupled links, in one example, withimproved stiffness and strength compared to previous designs, a largerrange of motion, and improved dynamic performance and visibilityproximate the surgical field for system users (in addition to otheradvantages), as is described in greater detail in U.S. application Ser.No. 11/613,800 filed Dec. 20, 2006, the full disclosure of which isincorporated by reference herein for all purposes.

For convenience, a manipulator such as manipulator 8 that is supportinga surgical tool used to manipulate tissues is sometimes referred to as apatient-side manipulator (PSM), while a manipulator 10 which controls animage capture or data acquisition device such as endoscope 11 may bereferred to as an endoscope-camera manipulator (ECM). The manipulatorsmay optionally actuate, maneuver and control a wide variety ofinstruments or tools, image capture devices, and the like which areuseful for surgery.

Referring now to FIGS. 2A-13B in conjunction with FIGS. 1A-1B, anapparatus, system, and method for sensing and feedback of forces to thesurgeon will be described with respect to using surgical instrumentsincluding strain gauges. It is noted that the below-describedinstruments are examples and various instruments that provide forcesignals may be modified within the scope of the present invention.

FIG. 2A shows a perspective view of a surgical instrument 100 thatincludes a shaft 110, a wrist 130 comprising joints for movement aboutaxes 112 and 114, and an end portion 120 that may be used to manipulatea surgical tool (e.g., a needle) and/or contact the patient. Thesurgical instrument also includes a housing 150 that operably interfaceswith a robotic manipulator arm, in one embodiment via a sterile adaptorinterface (FIGS. 12A-12C). Housing 150 includes the motion inputs andwrist cable actuator mechanisms. Applicable housings, sterile adaptorinterfaces, and manipulator arms are disclosed in U.S. patentapplication Ser. No. 11/314,040 filed on Dec. 20, 2005, and U.S.application Ser. No. 11/613,800 filed on Dec. 20, 2006, the fulldisclosures of which are incorporated by reference herein for allpurposes. Examples of applicable shafts, end portions, housings, sterileadaptors, and manipulator arms are manufactured by Intuitive Surgical,Inc. of Sunnyvale, Calif.

In a preferred configuration, end portion 120 has a range of motion thatincludes pitch about axis 112 and yaw about axis 114, which are parallelto the x- and y-axes respectively, and rotation about the z-axis asshown in FIG. 2B. These motions, as well as actuation of an endeffector, are done via cables running through shaft 110 and housing 150that transfer motion from the manipulator 8. Embodiments of driveassemblies, arms, forearm assemblies, adaptors, and other applicableparts are described for example in U.S. Pat. Nos. 6,331,181, 6,491,701,and 6,770,081, the full disclosures of which are incorporated herein byreference for all purposes.

It is noted that various surgical instruments may be used including butnot limited to tools with or without end effectors 120, such as jaws,scissors, graspers, needle holders, micro-dissectors, staple appliers,tackers, suction irrigation tools, clip appliers, cutting blades,irrigators, catheters, and suction orifices. Alternatively, the surgicalinstrument may comprise an electrosurgical probe for ablating,resecting, cutting or coagulating tissue. Such surgical instruments aremanufactured by Intuitive Surgical, Inc. of Sunnyvale, Calif.

In one example, (FIGS. 2A-2B) instrument 100 includes strain gaugesmounted onto the exterior surface of force transducer 140 orientedparallel to the longitudinal (lengthwise) axis of the instrument shaft,termed the z-axis. The two axes perpendicular to the shaft are calledthe x- and y-axes. The signals from the strain gauges are combinedarithmetically in various sums and differences to obtain measures oftransverse forces Fx and Fy exerted upon the instrument tip whilerejecting axial force Fz and torques Tx and Ty about the two axesperpendicular to the shaft axis. Forces exerted against end portion 120are detected by the force sensing elements, which may be operablycoupled to servo control via an interrogator 170 and a processor 180 fortransmitting these forces to master(s). Examples of instrumentsincluding strain gauges and methods of force sensing are disclosed inU.S. patent application Ser. No. 11/537,241 filed on Sep. 29, 2006, andU.S. application Ser. No. 11/553,303 filed on Oct. 26, 2006, the fulldisclosures of which are incorporated by reference herein for allpurposes.

In one example, various strain gauges 102 may be used, including but notlimited to optic fiber type gauges using Bragg grating or Fabry-Perottechnology. Optic fiber Bragg grating (FBG) gauges may be advantageousin that two sensing elements may be located along a single fiber 106 ata known separation L, thereby only requiring the provision of fourfibers along the force transducer 140 and the instrument shaft 110 toconnect eight strain gauges 102. Multiple FBGs can be written into afiber if they are formed in such a way as to use different ranges ofwavelengths. This is a particularly useful property for an embodimentcomprising a pair of rings 104 of strain gauges because only four fiberswould need to be passed thru the instrument shaft, each with two FBGsseparated by a known distance L.

In the disclosures referenced above, a force transducer mounted to thedistal end of an endoscopic surgical instrument shaft is described. Inone embodiment, the force sensor comprises two groups (rings) of fourstrain gauges located about the periphery of the sensor such that themembers of a group of four are situated in diametrically opposite pairsthat are 90 degrees or other alternating supplementary angle pairs (e.g.70 and 110 degrees) apart around the shaft and such that the two groupsor rings of four are a distance L apart along the shaft. In one aspect,it is desired to determine the side load (e.g., Fy) on the instrumenttip or jaws. By computing the bending moment due to the jaw side load ateach group of four strain gauges based on the difference of strains ondiametrically opposite strain gauge pairs and then subtracting themoment values at the two groups, a measure of the side load independentof wrist orientation and resulting effective lever arm length can bederived. Similarly, moments applied to the wrist clevis 160 and thedistal end of the force transducer by the actuation of the instrumentwrist axes and transmitted to the wrist clevis by the friction in thewrist pivots are felt equally at each group of four gauges and are thuseliminated by subtracting the moments measured at the two groups.Strains due to z-axis forces such as wrist actuator cable forces affectall strain gauges equally and are thus also eliminated by subtractingthe signals from the two groups of four gauges.

Referring now to FIG. 2B, Fabry-Perot or FBG sensing elements 102 andfibers 106 may be embedded in shallow grooves below the force transducer140 surface near the instrument shaft 110 distal end proximal to thewrist clevis 160 and end portion 120, and then epoxied or otherwisepotted into place.

Referring again to FIG. 2A, a perspective view of instrument 100including an optic fiber connector 300 a mounted in housing 150 isillustrated in accordance with an embodiment of the present invention.In this embodiment, a plurality of strain gauges (e.g., strain gauges102) embedded in a force transducer 140 at the distal end of shaft 110are coupled to an optic fiber splitter 306 by an optic fiber ribboncable 302 passing thru shaft 110. The optic fiber splitter 306 iscoupled to optic fiber connector 300 a by an optic fiber 326 that isrouted through housing 150 in an L-shaped path, in one example. Opticfiber connector 300 a is optically linkable with an optic fiberconnector 300 b (see also FIG. 13B) incorporated into the instrumentmechanical interface of a distal link 66 (see, e.g., FIG. 11) such thatinstallation of instrument 100 onto a manipulator 8 automatically formsan optical link with the instrument and signals from the instrumentstrain gauges related to force applied to the instrument tip may bepassed to an interrogator 170 and processor 180. Advantageously, thepresent invention avoids the need to carry external cabling to theinstrument.

Referring now to FIGS. 3A-3B, two different styles of fiber opticsplitters are illustrated. FIG. 3A illustrates a fiber optic splitter306 which is a 1×4 planar lightwave circuit (PLC) splitter. Lightentering waveguides 318 a-318 d embedded in a silica body 316 at a firstend of the silica body 316 is combined to exit at a second end of thesilica body 316, or alternatively light entering at the second endthrough waveguide 318 e is split equally among the four waveguides 318a-318 d to exit through the first end of the silica body.

FIG. 3B shows another fiber optic splitter which may be used inembodiments of the present invention. A fused biconic taper (FBT)splitter 320 is illustrated in which four fibers 326 are twistedtogether along a zone “C” at high temperature until their cores areclose enough to cause coupling of light among the cores with a resultsimilar to the PLC splitter discussed above. Three of the four fibers atone end are terminated to create a 1×4 splitter.

Referring now to FIGS. 4A-4B, longitudinal cross-section views areillustrated of lensed optical fibers 322 a and 322 b, which arecomponents of some embodiments of the present invention. A lensed fiber322 a or 322 b includes a small (e.g., 0.5 mm) ball lens 312 integratedwith an end of a fiber 326 either by bonding (FIG. 4A) or by fusing(FIG. 4B). Light emerging from a fiber core 328 diverges along a lightray path 330 and is then focused by the ball lens 312 resulting incollimated light 332 exiting the ball lens. Conversely, collimated lightentering the ball lens and aligned with the fiber core axis is focusedon the core end and then conducted along the core. The lensed fiber 322a or 322 b may be used as the optical component of an expanded beamconnector.

Referring now to FIG. 5, an aspheric lens fiber collimator 336, whichmay be used as the optical component of an expanded beam connector, isillustrated. Fiber collimator 336 includes an optic fiber 326, a housing331, and an aspheric lens 334. Light emerging from a core of the opticfiber 326 diverges along a light ray path 330 within housing 331 and isthen focused by aspheric lens 334, resulting in collimated light 332exiting the aspheric lens 334. Conversely, collimated light enteringlens 334 in alignment with the optical axis will be focused on the coreof fiber 326 and conducted along the core.

FIGS. 6A1-6A2 and 6B1-6B2 illustrate embodiments of a close coupled orintegrated collimating lens and a PLC splitter assembly. FIGS. 6A1-6A2show a perspective view and a partial cutaway perspective view of agradient index (GRIN) lens PLC splitter assembly 338 while FIGS. 6B1-6B2show a perspective view and a partial cutaway perspective view of a balllens PLC splitter assembly 340.

GRIN lens PLC splitter assembly 338 includes a fiber array block (FAB)304 operably coupled to a PLC fiber optic splitter 306, which isoperably coupled to a GRIN lens 308.

Ball lens PLC splitter assembly 340 includes a fiber array block (FAB)304 operably coupled to a PLC fiber optic splitter 306, which isoperably coupled to a ball lens 312.

In each case, collimated light entering the lens (lens 308 or 312)aligned with the optical axis is focused on the entrance to the PLCfiber optic splitter 306 and then split equally among the four otherwaveguides where the FAB 304 aligns four fibers so that their coresreceive the light. Both devices 338 and 340 also operate in the reversedirection where the fibers of a 4-wide fiber ribbon cable 302 arealigned by the FAB 304 so that light conducted through the ribbon cable302 enters the four waveguides and is combined through splitter 306 tothen emerge as a collimated beam from the lens (lens 308 or 312). Ineach case the device may be used as the optical component of an expandedbeam connector on the ribbon cable side of the connection.

FIGS. 7A-7B show views of an instrument including a fiber optic forcetransducer 140 similar to that described above with respect to FIGS.2A-2B. Similar elements are numbered the same and repetitivedescriptions are omitted to avoid redundancy. In this embodiment, theinstrument has four fibers emerging from the transducer 140 which aregathered directly into PLC splitter 306 (integrated with the transducer)so that a single fiber 326 passes through the instrument shaft 110 tothe rear housing 150 and expanded beam connector 300 a. The fiber strainrelief is in the form of a circular loop 326 a and the optical connector300 a is oriented to the rear for manual mating with an opticalconnector 300 b.

Referring now to FIGS. 8A-8C, different views are illustrated of a pairof back-to-back planar tapered features 342 of an instrument sterileadaptor (ISA) 70 which guide and align flexure mounted expanded beamconnectors (EBC) (or more generally optical connectors) 300 a, 300 b onthe manipulator (e.g., distal link 66 or instrument interface 61) and onthe instrument housing with an optical path 310 through the ISA 70. FIG.8A shows a perspective cross-sectional view of ISA 70, FIG. 8B shows atop perspective view, and FIG. 8C shows a bottom perspective view. Thisdesign of ISA 70 applies to the case of an instrument mounting motionwhich is transverse to the optical axis O_(A) of the connectors 300 a,300 b.

Referring now to FIGS. 9A-9C, flexure mounted EBCs on distal link 66(EBC 300 b) and the instrument housing 150 (EBC 300 a) are shown to beguided and aligned by conically tapered features 343 of the sterileadaptor 70 and conically tapered features 345 of the EBCs. Conicallytapered features 343 are provided as a canal through which conicallytapered features 345 of the EBCs may be received to guide and align theoptical axes O_(A) of the EBCs 300 a and 300 b. This design applies tothe case when the instrument mounting motion is parallel with theoptical axis O_(A) of the connectors.

FIGS. 10A-10D show orthographic views of an instrument rear housingincluding a fiber optic ribbon cable, a PLC fiber optic splitter, astrain relief loop of optical fiber or ribbon cable and an expanded beamoptic fiber connector in accordance with embodiments of the presentinvention. Various advantageous features of the optics in the rearhousing are shown.

FIG. 10A illustrates a U-shaped strain relieving “loop” of fiber (ribbonor single) to accommodate mechanical tolerances, ease assembly, andallow for thermal expansion during autoclaving. FIG. 10A furtherillustrates an optical connector including an aspheric lens 334 and asplitter 306 integrated within the optical connector.

FIGS. 10B and 10C similarly illustrate an L-shaped strain relieving loopof fiber (ribbon or single) to achieve similar advantages. It is notedthat a strain relief loop of optical fiber or ribbon cable may bend 90degrees, 180 degrees, or 360 degrees in one example. FIGS. 10B and 10Cfurther illustrate a splitter 306 integrated within housing 150 and anoptical connector including a lensed optical fiber 322 and a ball lens312, respectively.

Finally FIG. 10D illustrates a strain relief loop of fiber (ribbon orsingle) to achieve similar advantages, and a GRIN lens PLC splitterassembly 338 at the rear of housing 150 allowing for manual mating,assembly 338 including a PLC fiber optic splitter 306 operably coupledto a GRIN lens 308.

Referring now to FIGS. 11-13B, perspective views and respectiveperspective cross-sectional side views of a manipulator 8 including amanipulator arm link 50, a telescopic insertion axis 60, and an opticfiber connector 300 b are shown in accordance with an embodiment of thepresent invention. In FIG. 11, an interrogator 170 is operably coupledto optic fiber connector 300 b, and a computer 180 is optionally coupledto interrogator 170. The optic fiber technologies require aninterrogator unit that decodes the optically encoded strain informationfrom the instrument strain gauges into electrical signals compatiblewith the computer control hardware of the robotic surgical system. Aprocessor (e.g., processor 4 of FIG. 1) may then be used to calculateforces according to equations in conjunction with the signals from thestrain gauges/sensors. In one embodiment, interrogator 170 and computer180 is mounted on the manipulator, at the system main chassis, or on anequipment rack elsewhere in the surgical system, which may requirerouting of the optical fiber across the sterile boundary.

Communication between optic fiber connector 300 b and interrogator 170may be accomplished through a noise immune cable, such as a fiber opticcable 302 b, which is routed at least partially through manipulator arm8 in one example. Interrogator 170 may communicate with computer 180through various means, including but not limited to a serialinput/output. In one example, computer 180 may output raw strain gaugedata and/or resolved force/torque data in various formats, including butnot limited to hexadecimal and decimal integer formats.

Referring now to FIGS. 12A-12C and 13A-13B in conjunction with FIG. 11,the optic fiber connector 300 b is shown to be incorporated on aninstrument interface 61 of a distal link 66 of the manipulator and opticfiber cable 302 b is routed at least partially through the manipulatorlinkage. FIG. 12A-12C illustrates the coupling of instrument sterileadaptor (ISA) 70 onto instrument interface 61 of distal link 66. FIGS.13A and 13B illustrate the mounting of instrument 100 on ISA 70 and theoptical link between optic fiber connectors 300 a and 300 b through ISA70.

In one embodiment, telescopic insertion axis 60 includes a first link62, a second link or idler link 64 operably coupled to link 62, and athird link or distal link 66 operably coupled to idler link 64. Some ofthe manipulators 8 include a telescopic insertion axis 60, although inother embodiments, the manipulators may include a linear slidingcarriage as is described in greater detail in pending U.S. applicationSer. No. 11/613,800, filed Dec. 20, 2006, which is incorporated byreference herein for all purposes. In yet other embodiments, the linearinsertion motion of an attached instrument may result from thecoordinated motion of multiple hinged or revolute joint links.

Distal link 66 includes an instrument interface 61 (FIG. 11) foroperably coupling (electrically and/or physically) to ISA 70 (FIGS.12A-12C), which is configured to operably couple (electrically and/orphysically) to a housing of an instrument having an optic fiberconnector 300 a (e.g., housing 150 of FIGS. 13A and 14B). Optic fiberconnector 300 b is incorporated in instrument interface 61 to opticallylink with optic fiber connector 300 a of a mounted instrument throughISA 70. As shown in FIG. 12B, ISA 70 includes an optical path in theform of an aperture 310 or a lens through which optic fiber connector300 b is optically linkable to optic fiber connector 300 a (FIG. 13B)when the instrument is fully mounted on ISA 70. In one embodiment, thesterile adaptor is integrated with a drape that may be draped over therobotic surgical system, and in particular the manipulator system, toestablish a sterile barrier between the non-sterile manipulator arms andthe sterile field of the surgical procedure.

An example of applicable sterile adaptors and instrument housings aredisclosed in U.S. application Ser. No. 11/314,040, filed Dec. 20, 2005and in U.S. application Ser. No. 11/395,418, filed Mar. 31, 2006, thefull disclosures of which are incorporated by reference herein for allpurposes. An example of an applicable drape and adaptor is disclosed inpending U.S. application Ser. No. 11/240,113, filed Sep. 30, 2005, thefull disclosure of which is incorporated by reference herein for allpurposes. An example of an instrument interface is disclosed in pendingU.S. application Ser. No. 11/613,695, filed Dec. 20, 2006, the fulldisclosure of which is incorporated by reference herein for allpurposes.

It is noted that the optical connectors 300 a, 300 b (such as EBCs)described above may include the various collimating lenses andassemblies described above with respect to FIGS. 4A-6B2 and may bemounted on respective flexture beams 344 a, 344 b. The optic fiberconnectors may further include a fiber array block that receives a fiberribbon cable, a planar lightwave circuit (PLC) splitter operably coupledto the fiber array block, and a collimator lens operably coupled to thePLC splitter. The PLC splitter advantageously provides a compact meansfor combining signals from fiber optic sensors into fewer or preferablyone fiber and for separating signals on one or more fibers onto a largernumber of fibers.

The respective collimator lens of the optic fiber connectors enableslight to be transmitted between the optic fiber connectors with lesssensitivity to contamination of the mating surfaces, misalignment, andgap sensitivity by spreading light over a larger area, which may be moreeasily cleaned with minimal training of operating room staff. Althoughlight is spread over a larger area, the power level and spectraldistribution of the light is preserved to prevent degradation of signalsbetween the connectors. In one example, the collimator lens is formed ofan aspheric lens, a GRIN lens, a ball lens, or a lensed fiber. In otherembodiments, a plurality of lenses may be used.

Further, the PLC splitter may be mounted in the instrument housing andconnected by a single fiber with the EBC (FIGS. 2A, 10B, 10C) or the PLCsplitter may be integrated with (i.e. directly coupled to) the EBC(FIGS. 6A1, 6A2, 6B1, 6B2, 10A, 10D). In yet another embodiment the PLCsplitter may not be mounted in the housing but may be integrated withthe force transducer (FIG. 7A, 7B). The optic fiber connectors may alsohave their optical axis either aligned (FIGS. 9A-9C, 10A) or transverse(FIGS. 8A-8C, 10B, 10C) to the mating direction of the instrument withthe sterile adaptor and of the EBC pair. Finally, manual mating of theEBC pair at the rear of the instrument housing may be provided (FIGS.7A, 10D).

Alternatively, an optical multiplexer/demultiplexer (OMUX) chip canreplace the PLC splitter between the fiber array block and thecollimator lens. In one example, a planar arrayed waveguide grating(AWG) OMUX chip and its associated optic fiber connections can be used.Preferably, the AWG OMUX will be of the coarse wavelength divisionmultiplexer (CWDM) type. Each channel of the device will have awavelength pass band wide enough to accommodate the range of reflectedwavelength variations from fiber optic strain sensors on the fiberentering that channel. The variations include those due to appliedloads, temperature changes and also residual stress offsets from bondingthe fibers to the force transducer. The channel bandwidth must also besufficient to allow for temperature induced variations in the AWG OMUXchannel center wavelength. The AWG OMUX chip is of an athermaltemperature compensated type in a further example.

Advantageously, the present invention provides for reliable coupling ofa force sensing instrument to a manipulator, such that the effect ofoptical surface contamination and optical axis misalignment are reducedwhile signal quality is maintained. Furthermore, the need for a longcable attached to the instrument is eliminated, thus removing orlessening potential problems with rapid instrument interchange, steriledraping and handling, and instrument re-sterilization between uses.

Embodiments described above illustrate but do not limit the invention.It should also be understood that numerous modifications and variationsare possible in accordance with the principles of the present invention.Accordingly, the scope of the invention is defined only by the followingclaims.

We claim:
 1. A surgical instrument, comprising: a housing linkable witha manipulator arm of a robotic surgical system; a shaft operably coupledto the housing; a force transducer on a distal end of the shaft; aplurality of fiber optic strain gauges on the force transducer, one ormore of the plurality of fiber optic strain gauges being formed incorresponding ones of individual optical fibers; a single fiber opticsplitter coupled to all of the individual optical fibers; a fiber opticconnector mounted in the housing; a single optic fiber operably couplingthe fiber optic splitter to the fiber optic connector; a wrist jointoperably coupled to a distal end of the force transducer; and an endeffector operably coupled to the wrist joint.
 2. The instrument of claim1, wherein the fiber optic connector includes an expanded beamcollimator lens selected from the group consisting of a gradient indexlens, an aspheric lens, a ball lens, and a lensed optic fiber.
 3. Theinstrument of claim 1, wherein the plurality of fiber optic straingauges is operably coupled to the fiber optic splitter through thecorresponding individual optical fibers that are routed at leastpartially through the shaft.
 4. The instrument of claim 3, wherein thecorresponding individual optic fibers are configured in a loop at thehousing.
 5. The instrument of claim 1, wherein the fiber optic splitteris mounted in the shaft, and wherein the single optic fiber is routed atleast partially through the shaft.
 6. The instrument of claim 5, whereinthe single optic fiber is configured in a loop at the housing.
 7. Theinstrument of claim 1, wherein the fiber optic connector is configuredon the housing to transmit signals from the plurality of fiber opticstrain gauges to a second fiber optic connector mounted on a distal linkof the manipulator arm.
 8. The instrument of claim 7, wherein the fiberoptic connector approaches along its optical axis to mate with thesecond fiber optic connector.
 9. The instrument of claim 7, wherein thefiber optic connector approaches transversely to its optical axis tomate with the second fiber optic connector.
 10. The instrument of claim7, wherein the fiber optic connector is attached to the housing by aflexible member.
 11. The instrument of claim 10, wherein the fiber opticconnector is guided into optical alignment with the second fiber opticconnector by a tapered feature.
 12. The instrument of claim 1, whereinthe fiber optic connector is covered by a movable cover, the movablecover being opened by a mating action of the fiber optic connector witha second fiber optic connector.
 13. A method of operating a surgicalinstrument comprising: measuring a force at a tip of the surgicalinstrument by a plurality of fiber optic strain gauges on a forcetransducer on a distal end of a shaft of the surgical instrument, theplurality of fiber optic strain gauges being formed in correspondingones of individual optical fibers, wherein the surgical instrument ismounted on a robotic surgical manipulator, the surgical manipulatorincluding a first fiber optic connector, wherein the surgical instrumentincludes a fiber optic splitter and a second fiber optic connector, thefiber optic splitter being coupled to the plurality of fiber opticstrain gauges through the corresponding individual optical fibers, thesecond fiber optic connector being coupled to the fiber optic splitterwith a single optical fiber, and the second fiber optic connector beingoptically linkable with the first fiber optic connector of the roboticsurgical manipulator; and passing data from the plurality of fiber opticstrain gauges to the first fiber optic connector through the secondfiber optic connector.
 14. The method of claim 13, further comprisingcalculating a force based upon at least a difference of select signalsfrom the plurality of fiber optic strain gauges.